Color negative photographic elements are conventionally formed with superimposed red, green and blue recording layer units coated on a support.
The red, green and blue recording layer units contain radiation-sensitive silver halide emulsions that form a latent image in response to red, green and blue light, respectively. Additionally, the red recording layer unit contains a cyan dye image-forming coupler, the green recording layer unit contains a magenta dye image-forming coupler, and the blue recording layer unit contains a yellow dye image-forming coupler. Following imagewise exposure, the color negative photographic elements are processed in a color developer, which contains a color developing agent that is oxidized while selectively reducing to silver latent image bearing silver halide grains. The oxidized color developing agent then reacts with the dye image-forming coupler in the vicinity of the developed grains to produce a dye image. Cyan (red-absorbing), magenta (green-absorbing) and yellow (blue-absorbing) dye images are formed in the red, green and blue recording layer units, respectively. Subsequently the element is bleached (i.e., developed silver is converted back to silver halide) to eliminate neutral density attributable to developed silver and then fixed (i.e., silver halide is removed) to provide stability during subsequent room light handling.
Systems for processing color negative photographic elements are included among those disclosed in Research Disclosure, Item 38957, XVIII. Chemical development systems. Color developing agents are included among developing agents disclosed in Item 38957, XIX. Development, A. Developing Agents.
A type of color negative processing that is widely used is the Kodak Flexicolor.TM. color negative process. Since minor adjustments of the C-41 process are undertaken from time to time, the following detailed description is provided:
______________________________________ Develop 3'15" Developer 37.8.degree. C. Bleach 4' Bleach 37.8.degree. C. Wash 3' 35.5.degree. C. Fix 4' Fixer 37.8.degree. C. Wash 3' 35.5.degree. C. Rinse 1' Rinse 37.8.degree. C. ______________________________________ Developer Water 800.0 mL Potassium Carbonate, anhydrous 34.30 g Potassium bicarbonate 2.32 g Sodium sulfite, anhydrous 0.38 g Sodium metabisulfite 2.96 g Potassium Iodide 1.20 mg Sodium Bromide 1.31 g Diethylenetriaminepentaacetic acid 8.43 g pentasodium salt (40% soln) Hydroxylamine sulfate 2.41 g N-(4-amino-3-methylphenyl)-N-ethyl- 4.52 g 2-aminoethanol Water to make 1.0 L pH @ 26.7.degree. C. 10.00 +/- 0.05 Bleach Water 500.0 mL 1,3-Propylenediamine tetraacetic acid 37.4 g 57% Ammonium hydroxide 70.0 mL Acetic acid 80.0 mL 2-Hydroxy-1,3-propylenediamine tetraacetic acid 0.8 g Ammonium Bromide 25.0 g Ferric nitrate nonahydrate 44.85 g Water to make 1.0 L pH 4.75 Fix Water 500.0 mL Ammonium Thiosulfate (58% solution) 214.0 g (Ethylenedinitrilo)tetraacetic acid 1.29 g disodium salt, dihydrate Sodium metabisulfite 11.0 g Sodium Hydroxide (50% solution) 4.70 g Water to make 1.0 L pH at 26.7.degree. C. 6.5 +/- 0.15 Rinse Water 900.0 mL 0.5% Aqueous p-tertiary-octyl-(.alpha.- 3.0 mL phenoxypolyethyl)alcohol Water to make 1.0 L ______________________________________
When processing is conducted as noted above, negative dye images are produced. To produce a viewable positive dye image and hence to produce a visual approximation of the hues of the subject photographed, white light is typically passed through the color negative image to expose a second color photographic element having red, green and blue recording layer units as described above, usually coated on a white reflective support. The second element is commonly referred to as a color print element, and the process of exposing the color print element through the image bearing color negative element is commonly referred to as printing. Processing of the color print element as described above produces a viewable positive image that approximates that of the subject originally photographed.
A type of color print processing that is widely used is the Kodak.TM. RA-4 process. Since minor adjustments of the RA-4 process are undertaken from time to time, the following detailed description is provided:
______________________________________ Develop 45" Developer 35.degree. C. Bleach 45" Bleach-Fix 35.degree. C. Stabilize 90" Stabilizer 35.degree. C. ______________________________________ Developer Lithium salt of sulfonated polystyrene.sup.(1) 0.25 mL Triethanolamine 11.0 mL N,N'diethylhydroxylamine.sup.(2) 6.0 mL Potassium sulfite.sup.(3) 0.5 mL Color developing agent.sup.(4) 5.0 g Stain reducing agent.sup.(5) 2.3 g Potassium chloride 2.3 g Ethylenediaminetetraacetic acid, 3.0 g disodium salt monohydrate 3,4-Dihydroxy-1,2,5-benzenetrisulfonic 0.6 g acid, trisodium salt Potassium carbonate 25.0 g Water to make 1.0 L pH @ 35.degree. C. 10.04 ______________________________________ .sup.(1) 30% by weight aqueous solution. .sup.(2) 85% by weight aqueous solution. .sup.(3) 45% by weight aqueous solution. .sup.(4) 4(N-ethyl-N-2-methanesulfonylaminoethyl)-2-methylphenylenediamin sesquisulfate monohydrate. .sup.(5) Kodak Ektaprint 2 .TM. stainreducing agent (a stilbene compound)
Bleach-Fix
This is an aqueous composition of ammonium thiosulfate, sodium bisulfite, and an ammonium salt of the ferric complex of ethylenediaminetetraacetic acid having a pH of 6.2.
Stabilizing Composition
This is an aqueous composition of formaldehyde, sodium metabisulfite, potassium hydroxide, diethylene glycol, 5-chloro-2-methyl4-iso-thiazolin-3-one, the disodium salt of ethylenediaminetetraacetic acid, and 1-hydroxyethylidene-1,1,-diphosphonic acid having a pH of 7.2. The diethylene glycol serves as a solvent for the 5-chloro-2-methyl4-iso-thiazolin-3-one.
Color negative photographic elements are commonly exposed in a camera. Since lighting of the subject sought to be photographed can vary, it is usually desirable to obtain the highest levels of imaging speed consistent with the image structure (granularity and acuity) desired. One of the inefficiencies that limits the speed of color negative elements is that only a portion of the exposing light is absorbed within the recording layer units. The remainder of the light passes through unutilized.
If a color negative element were constructed with only the essential elements described above, the unabsorbed light would pass through the transparent support. At the back surface of the support the refractive index difference between the support and air causes a portion of the light to be back scattered. Any portion of back scattered light that is absorbed within the recording layer units results in halation, which reduces image sharpness. Therefore, it is common practice to provide a light absorbing (antihalation) layer either between the recording layer units and the support or on the back side of the support to absorb the light that is not absorbed by the recording layer units during its initial traverse. To allow printing through the fully processed color negative element, the antihalation layer is constructed to be decolorized during photographic processing.
Color print elements are typically exposed using a controlled light source. Therefore, lower imaging speeds than exhibited by color negative elements are typical. Since photographically processed color print elements are intended for viewing, the primary concern is for sharp images and low stain in minimum density areas. The incorporation of an antihalation layer increases image sharpness, but when incomplete decolorization of the antihalation layer occurs during photographic processing, the result is visually objectionable stain in minimum density areas.
Although color negative elements most commonly employ transparent film supports and color print elements most commonly employ white reflective (typically paper) supports, it is generally recognized that in theory the support of a photographic element can take any convenient form (1) capable of providing dimensional stability for the emulsion layers and (2) not detrimentally chemically interactive with the emulsion layers. Thus, a wide variety of materials, other than film and paper, such as glass, wood, and metal sheets and foils, as illustrated by Product Licensing Index, Vol. 92, December 1971, Item 9232, have been used from time to time as photographic supports. Research Disclosure and Product Licensing Index are published by Kenneth Mason Publications, Ltd., Dudley House, 12 North St., Emsworth, Hampshire P010 7DQ, England.